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Re: Rolled PE Caps

What about 3mil stainless?

Kevin

At 10:38 AM 4/11/99 -0600, you wrote:
>Original Poster: "Reinhard Walter Buchner" <rw.buchner-at-verbund-dot-net> 
>
>Hi Kevin,
>
>>Original Poster: "Kevin Wahila" <knw2-at-lehigh.edu>
>>
>>What would be the difference if you used aluminum foil rather than
>>aluminum flashing as the plates in a rolled poly cap?  It would just
>>be so much easier to roll.  Would it perform as well though?
>
>In terms of capacitance: No difference.
>In terms of holding up to the discharge current: No difference.
>
>I myself have sucessfully used kitchen foil in PE caps (while they
>lasted...;o)), because Al flashing is a rip-off in Europe. A 10m^2
>roll of 0.2mm (~0.010") costs around $60. It IS 99.9% pure
>aluminum, but who needs this in a cap (esp. with THAT price
>tag attached)?
>
>Disadvantages in using AL foil instead of flashing:
>--------------------------------------------------------------
>1.) It creases very easily: > trapped air >partial discharges >cap death
>
>2.) You canīt use the foil as a connector. It is way too fragile. This
>      means you need some solid way to connect the plate to the
>      connection terminal (like using straps and screws to attach
>      the connector to the actual cap plate.
>
>3.) Foil is ultra thin. It is nearly impossible to "round" the cut
>     edges. This, too can encourage corona production.
>
>Advantages:
>----------------
>1.) Cheaper.
>
>2.) Can be easily cut with scissors or paper cutters.
>
>3.) Lighter, flashing is heavy.
>
>4.) As it folds easier, the possibility of the edges "digging" into the
>     PE are almost non-existant. You can ruin a PE cap instantly,
>     using flashing, if the sharp (and stiff) edges dig into the PE
>     (effectively reducing the dielectrical thickness in a place where
>     you would rather have more than less thickness, because of
>     the high E-field present at this point)
>
>All in all, I think it is a matter of personal taste. On the other hand
>I donīt like rolled PE caps anymore (:o)).
>
>"Justin Hennigan" <justinh-at-interlaced-dot-net> asked:
>"And what about copper flashing?  it's a better conductor."
>
>While this IS true, it isnīt really necessary in cap. Copper
>flashing is much, much more expensive. Even commercial
>caps are built with aluminum.
>
>Coiler greets from germany,
>Reinhard
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